Windows 7 Enterprise Service Pack 1
SQL Developer 17.4.1.054.0712-x64
Oracle 12c
My SQL Developer database connections suddenly stopped working. I checked with Amazon RDS support and everything appears to be working correctly from their perspective. I right click on the DB connection an choose Properties, then click on the Test button and it displays Success. But if I then click on the Connect button a progress window pops up for a few seconds and the entire SQL Developer window freezes.
I was experiencing this behavior on SQL Developer version 4.2, so I installed version 17.1. The very first DB connection worked, but then I began experiencing the same thing on all subsequent DB connection attempts. Any help would be greatly appreciated.